/Engine/Source/Editor/SubobjectDataInterface/Public/SubobjectDataSubsystem.h
The Subobject Data Subsystem will produce the reflected subobject data based on a given root object. A root object can be anything, an actor instance clicked on via the level editor, a UBlueprint* by opening an asset, or something piped in from python or other scripting languages.
class USubobjectDataSubsystem : public [UEngineSubsystem](API\Runtime\Engine\Subsystems\UEngineSubsystem)